This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Human lipoxygenases (LOX)play pivotal roles in the biosynthesis of leukotrienes and other biologically active eicosanoids. Specific inhibitors that can modulate the physiological and pathological effects of these potent signaling compounds are of high interest. The overall goal of the investigations is to develop substrate-LOX models that can be used for the development of specific anti-LOX inhibitors. Specifically, we will: 1) model protein-substrate interactions in 8R-lipoxygenase. There is no crystal structure of a lipoxygenase in complex with its substrate arachidonic acid (AA) to reveal the structural basis for product specificity in this family of enzymes. The recent 1.85 [unreadable] resolution structure of 8R-LOX provides a strong foundation for model enzyme-substrate interactions. 2) "Test" the generally applicability of this model to lipoxygenases of different product specificity. The results of our research will help understand the mechanism of substrate recognition in lipoxygenases and facilitate drug design to target lipoxigenases. We have identified the binding site of 8R-Lox for the substrate , arachiconic acid using Internal Coordiante Mechanism (ICM). A model of the interactions between 8R-LOX and AA was generated. Sequence analysis and statistical analysis were applied to verify the model. The modeling results showed that the C-10 of AA is positioned against the catalytic Fe atom enclosed in 8R-LOX, which favors the catalytic process of 8R-LOX. The binding site of 8R-LOX has been defined. Further work will include simulating the interactions between 8R-LOX and AA using NAMD and generalizing the 8R-LOX:AA model to the LOX family.